Biologists at Zion National Park have detected pneumonia among the park's population of bighorn sheep.

Park managers issued an alert Tuesday urging visitors to report any coughing they hear from sheep inside the park.

Biologists identified a bighorn sheep ewe that was coughing and showing other signs of illness on July 20, according to the report. Shortly afterward, the ewe was euthanized for testing, and lab tests showed the presence of Mycoplasma ovipneumoniae, a baterium commonly associated with pneumonia in the species.

It was the first instance of a positive test for disease among the herd, which is tested regularly, but now officials have noticed additional bighorns exhibiting signs of illness, according to the report.

Biologist Jace Taylor said not all variations of Mycoplasma ovipneumoniae are equally lethal to bighorn sheep.(Photo: AP file photo)

The Utah Division of Wildlife Resources is working with park officials to monitor bighorns in and around the park to track the spread of the disease and better understand the risk to the greater herd, said Jace Taylor, an agency biologist.

He said fewer than 10 sick animals had been located, although that number could change from day to day.

"There are many variations of Mycoplasma ovipneumoniae, and not all are equally lethal to bighorn sheep," he said. "At the same time, no bighorn sheep in the Zion herd are known to have died from pneumonia."

Antibiotics and vaccines are not effective in treating the disease, but park staff will be able to better manage the herd for healthy animals if they can find those coughing or exhibiting other symptoms, Taylor said. Other signs of illness include constant head shaking and general lethargy.

Taylor said biologists are unsure of where the disease may have originated. It is transferable from some other species, he said, and may have come from a domesticated animal, but it is difficult to determine exactly where it started.

About 800 sheep make up the Zion herd, which roams within the national park boundaries and in the wildlands to the south and east. Taylor said the herd is well managed by the park and has historically maintained good health.

Anyone who has noticed a sheep showing symptoms is encouraged to call 435-772-0217 or email to Zion_Park_Information@nps.gov.